diff --git a/addons/mail/static/src/models/file_uploader.js b/addons/mail/static/src/models/file_uploader.js
index 5a30614c822..d3c422edb7a 100644
--- a/addons/mail/static/src/models/file_uploader.js
+++ b/addons/mail/static/src/models/file_uploader.js
@@ -126,7 +126,11 @@ registerModel({
         async _performUpload({ files }) {
             const composer = this.composerView && this.composerView.composer; // save before async
             const thread = this.thread; // save before async
-            const chatter = this.chatterOwner || this.attachmentBoxView && this.attachmentBoxView.chatter; // save before async
+            const chatter = (
+                (this.chatterOwner) ||
+                (this.attachmentBoxView && this.attachmentBoxView.chatter) ||
+                (this.activityView && this.activityView.activityBoxView.chatter)
+            ); // save before async
             const activity = this.activityView && this.activityView.activity; // save before async
             const uploadingAttachments = new Map();
             for (const file of files) {